Aerosol and Air Quality Research Laboratory, Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States.
College of Engineering, University of Miami, Miami, Florida 33146, United States.
Environ Sci Technol. 2021 Jul 6;55(13):8987-8999. doi: 10.1021/acs.est.1c00235. Epub 2021 Jun 16.
The highly infectious SARS-CoV-2 novel coronavirus has resulted in a global pandemic. More than a hundred million people are already impacted, with infected numbers expected to go up. Coughing, sneezing, and even talking emit respiratory droplets which can carry infectious viruses. It is important to understand how the exhaled particles move through air to an exposed person to better predict the airborne transmission impacts of SARS-CoV-2. There are many studies conducted on the airborne spread of viruses causing diseases such as SARS and measles; however, there are very limited studies that couple the transport characteristics with the aerosol dynamics of the droplets. In this study, a comprehensive model for simultaneous droplet evaporation and transport due to diffusion, convection, and gravitational settling is developed to determine the near spatial and temporal concentration of the viable virus exhaled by the infected individual. The exposure to the viable virus is estimated by calculating the respiratory deposition, and the risk of infection is determined using a dose-response model. The developed model is used to quantify the risk of short-range airborne transmission of SARS-CoV-2 from inhalation of virus-laden droplets when an infected individual is directly in front of the person exposed and the surrounding air is stagnant. The effect of different parameters, such as viral load, infectivity factor, emission sources, physical separation, exposure time, ambient air velocity, dilution, and mask usage, is determined on the risk of exposure.
高传染性的 SARS-CoV-2 新型冠状病毒已在全球引发大流行。已有超过 1 亿人受到影响,感染人数预计还会增加。咳嗽、打喷嚏,甚至说话都会产生携带传染性病毒的呼吸道飞沫。了解呼出的颗粒如何在空气中传播到暴露的人身上,以便更好地预测 SARS-CoV-2 的空气传播影响,这一点很重要。已经有许多关于引起 SARS 和麻疹等疾病的病毒空气传播的研究;但是,将传输特性与液滴的气溶胶动力学相结合的研究非常有限。在这项研究中,开发了一个综合模型,用于模拟由于扩散、对流和重力沉降导致的飞沫蒸发和传输,以确定感染个体呼出的具有感染力的病毒在近空间和时间上的浓度。通过计算呼吸沉积来估计暴露于具有感染力的病毒,并用剂量反应模型来确定感染风险。使用所开发的模型来量化当感染者直接站在暴露者面前且周围空气静止时,吸入载有病毒的飞沫时 SARS-CoV-2 的短程空气传播风险。确定了不同参数(例如病毒载量、传染性因子、排放源、物理隔离、暴露时间、环境空气速度、稀释和口罩使用)对暴露风险的影响。
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